Biosynthetic studies are in progress, concerned with the aminocyclitol antibiotics neomycin and validamycin, with the peptide antibiotics berninamycin A and the emerimicins, with the ansamycin antibiotics geldanamycin and streptovaricin, with the acyltetramic acid antibiotic streptolydigin, and with pactamycin, containing a shikimate-related "C7N" unit. Mutasynthetic efforts involve neomycin, pactamycin, and novobiocin (a coumarin-containing antibiotic) and synthetic efforts streptovaricin, nybomycin (a diazaanthracene), and streptolydigin, as well as tirandamycin and other related acyltetramic acids.